Happiness means the lack of suffering. It is not the common happiness of worldly people that is filled with desire and attachment, but the peaceful contentment of liberated beings.

1Myriad dharmas are only mind.
Mind is unobtainable.
What is there to seek?2If the Buddha-Nature is seen,
there will be no seeing of a nature in any thing.3Neither cultivation nor seated meditation —
this is the pure Chan of Tathagata.4With sudden enlightenment to Tathagata Chan,
the six paramitas and myriad means
are complete within that essence.

yea, ordinally happiness when ended, suffering occur there after.
Know that suffering is real, and happiness is false. As suffering don't become happiness, but happiness can become suffering.
Example, when eating good food. Eating your favourite food is happiness. But, if you were to continue to eat bowl after bowl of the same food, it becomes a suffering. This is how happiness become suffering. happiness if continue become suffering. But suffering if continue does not become happiness.
Example, when hungry, i am experiencing suffering. If one continue to stay hungry for 7 days, one will experience more suffering, not happiness. So suffering is real, and happiness is false.

Now neither suffering nor happiness is a good experience/realm. But one cannot sustain this state as time waits for no man.
Example when we are born, we are already walking towards the deathbed. Who can stop moving? Nobody.
But it's said that in Western Pureland, a Nirvanic Bliss(Ulitmate happiness), there's no all above three forms of sufferings.
In this samsaric world there's duality. Suffering and joy is dualistic view for one side or the other. If Ulitmate happiness has no suffering, then happiness is also gone. As it's on the same side with suffering. One gone, the other is gone too. It's when both suffering and joy is ended that bring forth the Ulitmate Reality of Nirvana (aka 極樂, Ulitmate Bliss). Thus called True bliss/joy. If there's joy, then joy is suffering and False. Ulitmate Joy is indeed inconcievable! Inconcievable mean cannot be said, nor cannot be think nor cannot be percieve.
Samsara is dimension of matter/karma controlling, you can't have your own wish or doing, hence suffering. Nirvana is a state/dimension of Mind/will/vow controlling, hence no suffering. There's this Utimate reality Buddha discovered.

_/\_
Amituofo!

"Enlightenment is to turn around and see MY own mistake, Other's mistake is also my mistake. Others are right even if they are wrong. i'm wrong even if i'm right. " - Master Chin Kung

All beings since their first aspiration till the attainment of Buddhahood are sheltered under the guardianship of Buddhas and Bodhisattvas who, responding to the requirements of the occasion, transform themselves and assume the actual forms of personality.

Thus for the sake of all beings Buddhas and Bodhisattvas become sometimes their parents, sometimes their wives and children, sometimes their kinsmen, sometimes their servants, sometimes their friends, sometimes their enemies, sometimes reveal themselves as devas or in some other forms.

plwk wrote:If the Pure Land only has happiness and if one has never suffered, how can one feel the happiness?

Go ask someone who has never suffered.

Profile Picture: "The Foaming Monk"
The Chinese characters are Fo (buddha) and Ming (bright). The image is of a student of Buddhism, who, imagining himself to be a monk, and not understanding the true meaning of the words takes the sound of the words literally. Likewise, People on web forums sometime seem to be foaming at the mouth. Original painting by P.Volker /used by permission.